The present invention relates to a hole plug for sealing a hole formed on a plate member such as a steel plate used for various types of products such as an automobile.
A hole plug basically includes a head portion and a foot portion projecting from a back surface of the head portion to be inserted into a hole to be blocked. As disclosed in Patent Reference No. 1, recently, this type of hole plug has a head portion having a roughly flat top surface without an opening for an aesthetic reason, and a foot portion having a foot portion main member projecting from a back surface of the head portion and several engaging claws turning toward the head portion side from an end of the foot portion main member for easy insertion into the hole. Each engaging claw can deforms (swing) around an end of the foot portion main member as a pivot in a radial direction of the foot portion main member. According to such a hole plug, when the hole plug is inserted into a hole formed in a plate member from the foot portion side, the hole plug is easily inserted as each engaging claw deforms inwardly in the radial direction, and a rim of the hole engages an engaging step portion at the end of the engaging claw. Therefore, the rim of the hole is held between the engaging step portion at the end of the engaging claw and the rim of the head portion, so that the hole plug is attached to the plate member and blocks the hole.
Patent Reference No.1                Japanese Patent Publication (Kokai) No. 2002-81428        
However, in the case where the rim of the hole is held between the rim of the head portion and the engaging step portion at the end of each engaging claw with the above-mentioned hole plug, not only the rim of the head portion is bent, but also the engaging claw is easily bent (deforming in a direction that the engaging step portion moves away from the back surface of the head portion). Thus, the bending amount (snapping force) of the head portion relative to the rim of the hole is low. Thus, it is difficult to obtain sufficient sealing ability relative to the rim of the hole based on the bending of the rim of the head portion.
Also, in the hole plug, the foot portion projecting from the back surface of the head portion may be formed of several plate-like split foot portions (uprising plate portions) for easy insertion, and each split foot portion can be easily bent when the hole plug is inserted. However, in this case, while the split foot portions are easily bent, some of the split foot portions may be bent backward and caught by the rim of the hole when the split foot portions are inserted. As a result, the other split foot portions are inserted in the hole while some of the split foot portions are not inserted. Therefore, the hole plug is not inserted properly.
The present invention has been made in order to solve the above-mentioned problems, and the first object is to provide a hole plug in which the ability to seal the rim of the hole to be blocked is improved while keeping the insertion ability to be made easily. The second object is to provide a hole plug in which the inserting operation can be performed properly while keeping the insertion ability to be made easily.
Further objects and advantages of the invention will be apparent from the following description of the invention.